In the early days, the birth of desktop computing resulted in technology that provided integration between the computer and the telephone: we call it Computer Telephony Integration or CTI. The concept was delightful to most technology-minded people, but it never really emerged as a ubiquitous desktop solution. Today IP-based telephony for business is a hot and growing market, and many vendors are providing some level of integration with the desktop computer - the most basic is a software-based phone, the most advanced is complete control of user communications and multiple forms of media from which the user may easily select. While this convergence of communications at the user's desktop provides value for end-user productivity, these applications are typically independent desktop applications and have little integration with other business applications.

Today CIOs focus a great deal on ways in which their business applications can be better leveraged to improve the efficiency and productivity of the business. Service-oriented architectures (SOA) are increasingly being seen as providing a framework for more effectively integrating disparate business systems. According to IDC, nearly 70 percent of CIOs are planning or implementing SOA as part of their business systems. However, the telecommunications element of their business is rarely even considered in the SOA process.

At a recent presentation I did at an IP communications industry event I asked for a show of hands on how many people knew what "VoIP" was. To no surprise, all people in the room raised their hands. I then asked how many knew what a "WSDL" was. I could see no hands in the air. Then I asked how many people knew what "SOA" was - no hands. "What you've just experienced is an example of the gap between telecommunications and business applications," I told the audience. Throughout many telephony-focused conferences one of the common themes is what the business value in IP-based telephony is, and a common answer is business applications. While telecommunications was making its move to IP-based software technology, other technologies were born out of a desire to provide a sharing of information and services among business applications, and one of them is Web services.

The general goal of Web services is to construct elements of business logic - services - that can be very easily used by other applications. The services themselves hide the complexity of their business logic from the consumers through simple interfaces that allow the services to be reused in many different applications. The service and the consumer of the service are described as being loosely coupled, an approach that allows complex composite solutions to be developed through leveraging multiple Web services.

The following are some of the key elements of Web service technology:

• XML (eXtensible Markup Language) is the core language of Web service technology. It provides a platform-neutral way to describe the data associated with any service transaction.
• SOAP (Simple Object Access Protocol) is the preferred means by which an application invokes a Web service. The protocol itself is written in XML.
• WSDL (Web Service Definition Language) is the specification of the interface that a Web service exposes to consumers. It describes the set of operations that the service makes available. The WSDL is also written in XML.

Some of the advantages of utilizing Web services are:

• Loosely Coupled: The high degree of abstraction that exists between the implementation and the consumption of the service frees the Web service client and the Web service provider from needing any knowledge of each other beyond inputs and outputs.
• Platform Neutral: Web services can be provided by or invoked on most if not all platforms today, even legacy platforms.
• Development Language Neutral: People are developing Web services using C/C++, C#, Java, Visual Basic, Python and others.
• Standards Are Architecture Neutral: They do not enforce client-server, peer-to-peer, or any other model, although practical implementation issues currently drive developers to client-server.
• Web Services Leverage Existing Standards: Leverage standards that are already in place for conventional Web server applications, including HTTP, secure sockets, and authentication.
• Relatively Lightweight: Therefore they can be easily deployed to small devices, for example PDAs and smartphones.

Through the maturing of Web service technology, enterprise applications are now being made to adapt to the specific needs of users rather than users being forced to adapt to the available functionality of applications. These developments are being applied to all aspects of information technology in the enterprise. It's only natural then to consider how business communications might be part of SOA frameworks, and since communication is a critical part of most business transactions, it seems logical that the enterprise-focused IP Telephony industry would consider its role in the development of SOA.

I have also started speaking to audiences of business software architects and CIOs in venues that are focused on approaches for SOAs. As part of my presentation, I introduce the evolution of telecommunications as a business application and how the result will provide a natural fit into their SOA planning. During these presentations it has become equally clear that that telecommunications are not being considered as part of SOA initiatives. Traditionally, business telecommunications are delivered through PBX systems that are proprietary, closed, and stand-alone. These represent expensive hardware systems installed in separate phone rooms or separate areas of the data center, operated over a separate wiring infrastructure, and managed by a team of highly trained telecom engineers. These systems run independently from every other aspect of the business.

It is well known that traditional PBXs are becoming IP-based PBXs, but more important, PBXs are becoming all software implementations that not only adapt to the business application environment, but are purposely built to align with business applications and the natural interfaces of the business application environment. Now, traditionally closed communications services are being fully exposed through Web services, within an SOA framework, to enable easy and comprehensive integration with other enterprise-class applications.

As an open, software-based business application, the PBX function can be abstracted away from the underlying network infrastructure and any telephones or gateways that it supports. As a software application, it can be architected as an open mission-critical communications solution rather than as a closed stand-alone system. The best approach provides a distributed application that is able to operate on any number of networked servers. The servers can be centralized or set up over any wide geographic area, with no one server acting as a single point of failure.

These new solutions provide a very rich feature set to their users that go far beyond the traditional audio feature sets of legacy PBX systems. At the heart is a presence engine that allows users to view the presence state (on the phone, in a meeting, out to lunch, etc.) of colleagues so that an appropriate means of communication can be chosen. If a colleague is on the phone then a user might choose to send a text message to the colleague requesting a call back when they free up. Additionally, these systems have the ability to "find" (or intelligently route calls to) a user based on a number of criteria, including presence state, time of day, and caller ID. As a business software application, they are able to offer this rich set of capabilities as services to other applications. In essence, IP PBX communications can become part of the core fabric underlying all business processes. Most business applications do not want to know or need to know about the complexity of establishing audio, video, or data communications between users. Web service technology provides an ideal integration approach, whereby the complexity of communications is shielded by the IP PBX from the business application, yet at the same time the technology provides a very simple approach for invoking the services.

Going forward, CIOs will have the power to deploy telecommunications as an enterprise-class software application running on their underlying data network, in order to provide a rich set of communications services, and most important, to integrate with other enterprise-class applications. By doing so, new business-advancing levels of efficiencies and productivity will be achieved - not only in the IT shop but also for end users.

The vision of an SOA providing a framework for next-generation enterprise telecommunications services has become a reality through the maturing of Web service technology. Communications Web services are a new approach for business communications that promise CIOs the opportunity to rethink how the enterprise is architected and to establish communications as the essential fabric supporting all of their business processes.

Such communications services can now take their rightful place alongside collaborating business processes to allow enterprises to achieve the dream of a fully integrated service-oriented architecture, an architecture that can grow with the business and grow with technology. Ultimately, communications Web services create a more integrated, optimized - and more competitive business.